Translocation and accumulation of cadmium and lead in the tissues of 39 rape cultivars grown in a polluted farmland

To investigate the differences in cadmium (Cd) and lead (Pb) uptake and translocation among rape cultivars and genotypes and select suitable rape cultivars for both safe production and soil remediation, a field experiment was carried out with 39 rape cultivars of three genotypes on a farmland polluted with Cd and Pb in eastern Hunan Province, China. The Cd and Pb contents in rape tissues were measured, and the amount of Cd and Pb removed was calculated. The results showed that Cd in rape plants accumulated mostly in stems, while Pb accumulated mostly in roots. The Cd accumulation in various rape tissues followed the sequence stem > root > husk > rapeseed, while the Pb accumulation followed the sequence root > stem > husk > rapeseed. The total Cd and Pb removed by planting rape were 4.50–23.6 g ha−1 and 5.85–13.7 g ha−1, respectively, and the Cd and Pb contents in rapeseeds were in the range 0.11–0.47 mg kg−1 and 0.03–0.84 mg kg−1, respectively. Only the Pb content in rapeseed of “Youyan 9” exceeded the limit of the maximum levels of contaminants in foods (GB2762-2017, Pb ≤ 0.2 mg kg−1). In this experiment, the roots of most rape cultivars showed a greater capacity for Cd transport, while the stems showed a greater capacity for Pb transport. Except for the TFstem-husk for Cd, there were no significant differences in the TFs and BAFs of 39 rape cultivars, and clear variations in Cd content were found in the stems of the three genotypes, while there was no significant difference in the Cd and Pb contents in the other tissues. In the farmland polluted with Cd and Pb, planting “Xiangzayou 695” and “Youyan 2013” not only reduced soil pollution but also allowed the production of safe rapeseed.